How to sync a Linux secondary DHCP server?

Thomas Markwalder tmark at
Tue Jul 31 14:16:56 UTC 2018

Hello Sandra:

Yes. Anything specified via configuration file must be sync'd outside of 
Fail over, in ISC DHCP, is based on draft RFC:

It does not call for exchanging information beyond lease and server 
state information, and
was written such that any two servers which adhere to it, should be 
inter operable.  At least
that was the original intent.

Host reservations are "a policy mechanism" and as such are not governed 
by RFCs. Thus they
are entirely specific to DHCP server implementations.


Thomas Markwalder
ISC Software Engineering

On 07/31/2018 10:00 AM, Sandra Schlichting wrote:
>> One point of clarification,  Host reservations are not synchronized
>> between servers via fail over.  Any host reservations you have in one
>> configuration file,  you must include in the peer server's configuration
>> file.  For dynamic reservations (i.e. those that do not include a fixed
>> address), the leases allocated for each host will be synchronized
>> (assuming they come from within a FO pool), but not the actual
>> reservation specifications.
> So for the reservation I would have to rsync/scp them over?
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